(i) Field of the Invention PA1 (ii) Description of the Related Art PA1 0.30&lt;L/D&lt;1.20. . . (1) PA1 0.02&lt;t/I&lt;0.20. . . (2)
The present invention relates to a structure of a rotor of an electric motor which is used in a compressor or the like.
Hitherto, a rotor of such a kind of an Electric motor for a compressor of this kind, more particularly, a rotor of an electric motor called a brushless DC motor has a structure constructed in such a manner that a rotor core is constructed by laminating a plurality of iron plates for the rotor and caulking and fixing them, four (in case of four poles) magnetic bodies (permanent magnets) are inserted along the outer periphery of the rotor core, and notches are formed among the magnetic bodies on the outer periphery of the rotor core to construct salient poles, thereby preventing a short-circuit of a magnetic flux.
Trough holes to caulk and fix upper and lower non-magnetic end surface members or the like are formed in the iron plates for the rotor of the rotor core. The end surface members, a disk for oil separation, and the like are caulked and fixed to the rotor core by inserting rivets to the through holes.
On the other hand, as shown in FIG. 16, in Japanese Patent Application Laid-Open No. 47-27302, a structure constructed in such a manner that a plurality of flat permanent magnets 100 are radially inserted from the center of a rotor 101 so that those magnetic paths point to the tangent directions has been disclosed.
In the former rotor, however, since the through holes are formed inside the notches, namely, between the magnetic bodies, in case of four or more magnetic poles, the through holes exist on the magnetic paths formed over between the adjacent magnetic bodies (magnetic poles). Consequently, a problem that a magnetic resistance increases in portions of the through holes, so that an output of the motor deteriorates occurs.
In the latter construction, after the four magnets 100 were inserted to four slots 102, respectively, it is necessary to arrange run-out preventing members 103 for preventing that the magnets 100 are run out due to a centrifugal force to the outer periphery. Therefore, the number of parts increases and the operation becomes troublesome. Since there are four magnets, there is a problem such that there is a limitation for a magnetic force and intended characteristics cannot be derived.